The present invention relates generally to packaging techniques. More particularly, the invention includes a method and structure for forming composite substrate structures. Merely by way of example, the invention has been applied to the bonding of a patterned silicon substrate and a transparent substrate. The method and structure can be applied to other applications as well, such as packaging of optical sensors, electromechanical sensors, optoelectronic components, and the like.
Visual display technologies have developed rapidly over the years. Most particularly, electronic displays for the presentation of video signals have undergone rapid development in recent years and are experiencing increasing levels of customer adoption. A variety of video displays have utilized cathode ray tube (CRT), liquid crystal display (LCD), and spatial light modulator (SLM) technology. Both LCDs and SLMs are typically used in projection display units, in which light is first projected onto electrically activated pixel elements of the LCD or SLM and subsequently re-imaged at a display screen.
A particular SLM technology sold by Texas Instruments Incorporated (TI) of Dallas, Tex., is referred to as Digital Light Processing™ or DLP™. DLP relies upon a few hundred thousand tiny mirrors, which form an array of micro-mirrors. Each of the mirrors is hinged and an actuator is attached to each of the hinges. The actuator is often activated by electrostatic energy that can tilt each of the mirrors at high frequency. The moving mirrors can modulate light, which can be transmitted through a lens and then displayed on a screen. Although DLP has been successful, it is often difficult to manufacture and subject to low yields, etc. DLP is also manufactured using MEMS based processing techniques. Such MEMS based processing techniques are often costly and difficult to scale up for efficient processing. More specifically, packaging techniques used for MEMS are often costly and difficult to scale up to production levels.
From the above, it is seen that an improved technique for packaging devices is desired.